1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
4 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
5 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
6 * Copyright 2003 PathScale, Inc.
9 #include <linux/stddef.h>
10 #include <linux/err.h>
11 #include <linux/hardirq.h>
13 #include <linux/module.h>
14 #include <linux/personality.h>
15 #include <linux/proc_fs.h>
16 #include <linux/ptrace.h>
17 #include <linux/random.h>
18 #include <linux/slab.h>
19 #include <linux/sched.h>
20 #include <linux/sched/debug.h>
21 #include <linux/sched/task.h>
22 #include <linux/sched/task_stack.h>
23 #include <linux/seq_file.h>
24 #include <linux/tick.h>
25 #include <linux/threads.h>
26 #include <linux/resume_user_mode.h>
27 #include <asm/current.h>
28 #include <asm/mmu_context.h>
29 #include <linux/uaccess.h>
30 #include <as-layout.h>
31 #include <kern_util.h>
34 #include <registers.h>
35 #include <linux/time-internal.h>
38 * This is a per-cpu array. A processor only modifies its entry and it only
39 * cares about its entry, so it's OK if another processor is modifying its
42 struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
44 static inline int external_pid(void)
46 /* FIXME: Need to look up userspace_pid by cpu */
47 return userspace_pid[0];
50 int pid_to_processor_id(int pid)
54 for (i = 0; i < ncpus; i++) {
55 if (cpu_tasks[i].pid == pid)
61 void free_stack(unsigned long stack, int order)
63 free_pages(stack, order);
66 unsigned long alloc_stack(int order, int atomic)
69 gfp_t flags = GFP_KERNEL;
73 page = __get_free_pages(flags, order);
78 static inline void set_current(struct task_struct *task)
80 cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
81 { external_pid(), task });
84 extern void arch_switch_to(struct task_struct *to);
86 void *__switch_to(struct task_struct *from, struct task_struct *to)
88 to->thread.prev_sched = from;
91 switch_threads(&from->thread.switch_buf, &to->thread.switch_buf);
92 arch_switch_to(current);
94 return current->thread.prev_sched;
97 void interrupt_end(void)
99 struct pt_regs *regs = ¤t->thread.regs;
103 if (test_thread_flag(TIF_SIGPENDING) ||
104 test_thread_flag(TIF_NOTIFY_SIGNAL))
106 if (test_thread_flag(TIF_NOTIFY_RESUME))
107 resume_user_mode_work(regs);
110 int get_current_pid(void)
112 return task_pid_nr(current);
116 * This is called magically, by its address being stuffed in a jmp_buf
117 * and being longjmp-d to.
119 void new_thread_handler(void)
121 int (*fn)(void *), n;
124 if (current->thread.prev_sched != NULL)
125 schedule_tail(current->thread.prev_sched);
126 current->thread.prev_sched = NULL;
128 fn = current->thread.request.u.thread.proc;
129 arg = current->thread.request.u.thread.arg;
132 * callback returns only if the kernel thread execs a process
135 userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs);
138 /* Called magically, see new_thread_handler above */
139 void fork_handler(void)
143 schedule_tail(current->thread.prev_sched);
146 * XXX: if interrupt_end() calls schedule, this call to
147 * arch_switch_to isn't needed. We could want to apply this to
148 * improve performance. -bb
150 arch_switch_to(current);
152 current->thread.prev_sched = NULL;
154 userspace(¤t->thread.regs.regs, current_thread_info()->aux_fp_regs);
157 int copy_thread(struct task_struct * p, const struct kernel_clone_args *args)
159 unsigned long clone_flags = args->flags;
160 unsigned long sp = args->stack;
161 unsigned long tls = args->tls;
162 void (*handler)(void);
165 p->thread = (struct thread_struct) INIT_THREAD;
168 memcpy(&p->thread.regs.regs, current_pt_regs(),
169 sizeof(p->thread.regs.regs));
170 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0);
172 REGS_SP(p->thread.regs.regs.gp) = sp;
174 handler = fork_handler;
176 arch_copy_thread(¤t->thread.arch, &p->thread.arch);
178 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
179 p->thread.request.u.thread.proc = args->fn;
180 p->thread.request.u.thread.arg = args->fn_arg;
181 handler = new_thread_handler;
184 new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
187 clear_flushed_tls(p);
190 * Set a new TLS for the child thread?
192 if (clone_flags & CLONE_SETTLS)
193 ret = arch_set_tls(p, tls);
199 void initial_thread_cb(void (*proc)(void *), void *arg)
201 int save_kmalloc_ok = kmalloc_ok;
204 initial_thread_cb_skas(proc, arg);
205 kmalloc_ok = save_kmalloc_ok;
208 void um_idle_sleep(void)
210 if (time_travel_mode != TT_MODE_OFF)
216 void arch_cpu_idle(void)
218 cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
220 raw_local_irq_enable();
223 int __uml_cant_sleep(void) {
224 return in_atomic() || irqs_disabled() || in_interrupt();
225 /* Is in_interrupt() really needed? */
228 int user_context(unsigned long sp)
232 stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
233 return stack != (unsigned long) current_thread_info();
236 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
238 void do_uml_exitcalls(void)
242 call = &__uml_exitcall_end;
243 while (--call >= &__uml_exitcall_begin)
247 char *uml_strdup(const char *string)
249 return kstrdup(string, GFP_KERNEL);
251 EXPORT_SYMBOL(uml_strdup);
253 int copy_to_user_proc(void __user *to, void *from, int size)
255 return copy_to_user(to, from, size);
258 int copy_from_user_proc(void *to, void __user *from, int size)
260 return copy_from_user(to, from, size);
263 int clear_user_proc(void __user *buf, int size)
265 return clear_user(buf, size);
268 static atomic_t using_sysemu = ATOMIC_INIT(0);
269 int sysemu_supported;
271 void set_using_sysemu(int value)
273 if (value > sysemu_supported)
275 atomic_set(&using_sysemu, value);
278 int get_using_sysemu(void)
280 return atomic_read(&using_sysemu);
283 static int sysemu_proc_show(struct seq_file *m, void *v)
285 seq_printf(m, "%d\n", get_using_sysemu());
289 static int sysemu_proc_open(struct inode *inode, struct file *file)
291 return single_open(file, sysemu_proc_show, NULL);
294 static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
295 size_t count, loff_t *pos)
299 if (copy_from_user(tmp, buf, 1))
302 if (tmp[0] >= '0' && tmp[0] <= '2')
303 set_using_sysemu(tmp[0] - '0');
304 /* We use the first char, but pretend to write everything */
308 static const struct proc_ops sysemu_proc_ops = {
309 .proc_open = sysemu_proc_open,
310 .proc_read = seq_read,
311 .proc_lseek = seq_lseek,
312 .proc_release = single_release,
313 .proc_write = sysemu_proc_write,
316 int __init make_proc_sysemu(void)
318 struct proc_dir_entry *ent;
319 if (!sysemu_supported)
322 ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_ops);
326 printk(KERN_WARNING "Failed to register /proc/sysemu\n");
333 late_initcall(make_proc_sysemu);
335 int singlestepping(void * t)
337 struct task_struct *task = t ? t : current;
339 if (!test_thread_flag(TIF_SINGLESTEP))
342 if (task->thread.singlestep_syscall)
349 * Only x86 and x86_64 have an arch_align_stack().
350 * All other arches have "#define arch_align_stack(x) (x)"
351 * in their asm/exec.h
352 * As this is included in UML from asm-um/system-generic.h,
353 * we can use it to behave as the subarch does.
355 #ifndef arch_align_stack
356 unsigned long arch_align_stack(unsigned long sp)
358 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
359 sp -= prandom_u32_max(8192);
364 unsigned long __get_wchan(struct task_struct *p)
366 unsigned long stack_page, sp, ip;
369 stack_page = (unsigned long) task_stack_page(p);
370 /* Bail if the process has no kernel stack for some reason */
374 sp = p->thread.switch_buf->JB_SP;
376 * Bail if the stack pointer is below the bottom of the kernel
377 * stack for some reason
382 while (sp < stack_page + THREAD_SIZE) {
383 ip = *((unsigned long *) sp);
384 if (in_sched_functions(ip))
385 /* Ignore everything until we're above the scheduler */
387 else if (kernel_text_address(ip) && seen_sched)
390 sp += sizeof(unsigned long);
396 int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
398 int cpu = current_thread_info()->cpu;
400 return save_i387_registers(userspace_pid[cpu], (unsigned long *) fpu);